The surface of Venus is so hot that the lower crust may be weak enough to allow decoupling of mantle and crust. An analytic model of such decoupling assumes that the shallow mande forms the top boundary layers of large scale mantle convection cells. Crustal flow is driven by the motion of the marie and by topographically induced pressure gradients. The model predicts that the lowest lowlands ar...

Mountains on rapidly rotating neutron stars efficiently radiate gravitational waves. The maximum possible size of these mountains depends on the breaking strain of the neutron star crust. With multimillion ion molecular dynamics simulations of Coulomb solids representing the crust, we show that the breaking strain of pure single crystals is very large and that impurities, defects, and grain bou...

Introduction: Many new meteorites representing rare achondrite groups are being recovered from both hot and cold deserts. A significant fraction of these meteorites are both coarse-grained in texture and small in size, making accurate determinations of bulk rock compositions rather challenging. We successfully obtained elemental analyses of several angrites using ~1 mm 2 rasters of polished sec...

Ferromanganese crusts record seawater isotope history for several elements useful for paleoceanography. Interpreting crust isotope profiles, however, requires an assessment of the rate of diffusion of each element within the crust. We address this issue using Uand Th-isotope profiles, coupled with concentration measurements of some trace elements whose isotopes are often measured in crusts. A d...

Maharloo Lake is one of the salty lakes located in the southeast of Fars province, Iran. Presence of salt domes has a significant role in its salinity. Magnesium-sodium chloride and sodium sulfate are dominant salts of the lake. Due to the drying up of lake, widespread lands surrounding the area are exposed to secondary salinity. It seems necessary to investigate the changes to find salinity le...

Introduction: When a large hypervelocity impact occurs on a planetary body such as Mars, the kinetic energy of the impactor is partitioned primarily into 1) kinetic energy of the planetary crust and mantle as they deform and flow in response to the impact, 2) heating, melting and vaporization of impactor, crust and mantle material and 3) shockwaves that travel throughout the entire volume of th...

Magnetotelluric exploration has shown that the middle and lower crust is anomalously conductive across most of the north-to-south width of the Tibetan plateau. The integrated conductivity (conductance) of the Tibetan crust ranges from 3000 to greater than 20,000 siemens. In contrast, stable continental regions typically exhibit conductances from 20 to 1000 siemens, averaging 100 siemens. Such p...

Motivated by the remarkably narrow range of measured spin frequencies of ∼ 20 accreting (and weakly magnetic) neutron stars in the Galaxy, Bildsten (1998a) conjectured that their spin-up had been halted by the emission of gravitational waves. If so, then the brightest persistent X-ray source on the sky, Scorpius X-1, should be detected by gravitational wave interferometers within ten years. Bil...

We predict gravity from a three-dimensional Vp model of the upper crust and compare it to the observed isostatic residual gravity field. In general this comparison shows that the isostatic residual gravity field reflects the density variations in the upper to middle crust. Both data sets show similar density variations for the upper crust in areas such as the Peninsular Ranges and the Los Angel...

since heavy metals are considered as one of the major pollutants threatening, the main goal of this study was to bring out the concentrations of pb, zn and mn in the surface sediments off bushehr in the persian gulf. for this purpose, after collection of samples, the concentrations of the three metals in surface sediments were measured through the atomic absorption. the results were compared wi...